pic: Team 980 Breakaway robot

[David Brinza]

Originally Posted by Lil' Lavery

Why such large sprockets? Are you using your belts to double as a tread drive while you go over the bump?

Exactly. The treads are off the floor except when we traverse the bump.

Originally Posted by RogerR

It appears that you have a suspension on the front wheels, with the pivot 3"-4" ahead of the center wheel axle. If this is the case, it seems as though the center to center distance will change between the front and middle wheels, which would lead to the belt tensioning and loosening based on were the front suspension is in its travel.

If the above is true, how do you handle this?

The center-to-center distance radius is large, but the compression of the shock is quite limited, so the amount of tension change isn't large. We are considering a very simple idler (just a roller on a spring), if we find belt slippage to be a problem.

Originally Posted by Chris is me

Early in the season there was talk on 1714 of using a 6 wheel drive with pulleys between the wheels like this one to double as power transmission and bump climbing aid. Is this why you guys decided to go for timing belt, or did you guys have other reasons? I'm interested in alternatives to roller chain for drivetrains, so any info is appreciated.

Yes, "dual use" mentality was at work here. This is the first time we've deviated from chain in our drive system. We'll know in two weeks whether we made the right call.